When I first came to Japan, I thought "Where is all the wildlife?" You know, everyday urban-adapted wildlife like we have in the United States such as squirrels, raccoons, and chipmunks. . . Such animals and small rodents can be found living in almost any city or city park in the U.S., but in Japan, with the exception of the City Mouse, animals just don't seem to move to the cities. Less opportunity, I guess.
Even in the Japanese countryside, I've noticed a lack of road kill. On the small island where I live, which is part of the Seto Inland Sea National Park, the only wild animals I've seen are birds, ducks and snakes. I've never even seen a mouse here. A few years ago some deer swam out from the mainland, but apparently the accommodations weren't good enough because they didn't stay long.
You won't find many wild animals in urban areas or on the mainland of Japan unless they've escaped from the zoo. Whether Japan once had a lot of resident wildlife or not, I do not know. But perhaps this lack of animalia is what has caused the Japanese to create "captive wildlife."